1. Field of the Invention
This invention relates to a door lock mechanism and more particularly to a door lock mechanism for holding a door in a closed position relative to a frame supporting the door in locked or unlocked condition, and for aligning the door with a second door or with the frame.
2. Description of Related Art
The invention is particularly useful in conjunction with doors which provide access to enclosures such as trophy cases, china cabinets, gun cabinets, and display cases of myriad types. In each of these settings it is desirable to be able to retain the door in a closed position for reasons of safety to passersby and security to the contents of the enclosure. It is also desirable that the door be easily moveable from the closed position by the application of an outwardly directed force to the door; however, the degree of force necessary to open the door should not be so slight as to cause it to be opened inadvertently, for example as a result of vibrations caused by passersby.
Examples of means used to retain doors or similar elements in a closed position are disclosed in Falk U.S. Pat. No. 1,937,425, issued Nov. 28, 1933, which discloses a latching mechanism suitable for use with an automobile glove compartment; Francis U.S. Pat. No. 1,762,015, issued Jun. 30, 1930, which discloses a means for securing a cash box cover in a closed position; and Johnson U.S. Pat. No. 1,013,553, issued Jan. 2, 1912. Similarly, Frost U.S. Pat. No. 2,038,835, issued Apr. 28, 1936, discloses an enlarged head on a latch member which is received between a pair of spring-loaded plungers to secure the doors of a vehicular trailer in a closed position. Williams U.S. Pat. No. 2,097,653, issued Nov. 2, 1937, discloses a pair of opposed spring-loaded bullet catches which are received by slots in a plate disposed between the catches.
Sprick et al. U.S. Pat. No. 3,752,520, issued Aug. 14, 1973, discloses a rounded stud head which is received by a slot in a latch plate that must be actuated manually to release the stud from holding a cargo container door in the closed position.
It is often advantageous to be able to lock the door in its closed position, for example to protect the contents of the enclosure from theft, vandalism, or unintended damage. Accordingly, some prior patents disclose, in combination with a means for releasably retaining a member in a given position, a means for locking the member in that position. An example is the patent to Falk noted above. Another is Hudson U.S. Pat. No. 1,194,022, issued Aug. 8, 1916, which discloses a device for locking a window sash in a window frame.
Finally, there are many instances in which it is important for the door to be aligned with its frame when it is closed or for one door to be aligned with another. If the door is not properly aligned, there may be unnecessary stress imposed on the door, its frame, the hinge or other means by which the door is secured to the frame, as well as the door's closing and locking mechanisms. This stress can cause accelerated deterioration of the foregoing components and require early repair or replacement. Also, a misaligned door may amount to an invitation to attempt unauthorized entry of the disclosure. Furthermore, especially in the case of furniture of quality, a properly aligned door contributes to the article's overall aesthetic appearance.
Since the means for retaining a door in a closed position, locking the door in that closed position, and aligning the door within its frame or relative to another door are closely related and often simultaneously utilized, it is advantageous to provide a single mechanism which incorporates the means necessary for realizing all these features.